High-potential spark-coil.



U. H. THOPJDARSON.

HIGH POTENTIAL SPARK COIL.

APPLICATION FILED DEG.23,1907.

899,634, Patented Sept. 29, 1908.

2 SHEETS-SHEET 1.

Q t [I im'vbme cm U. H. THORDARSON. HIGH POTENTIAL SPARK COIL.

APPLICATION FILED DEG. 23, 1907.

899,634, Patented Sept, 29, 1908.

2 SHEETSSHEET 2.

CHESTER ii. TnoRnAnsoN, or CHICAGO, ILLINOIS.

man-PorEn'rIAL sranx-corn.

Specification of Letters Patent.

Patented. Sept. 29, 1908.

Application filed. December 23, 1967. Serial No. 407,808.-

To all whom itmay concern:

Be it known that I, CHESTER H. Tnon- DARSON, a citizen of the United States, residing at Chicago, in the county of Cook, State of Illinois, have made a certain new and useful Invention in High-Potential Spark-Coils, of which the following is a specification.

' This invention relates to high potential spark coils.

The object of the invention is to provide a construction of spark coil in which the spark produced is short and has a tendency to game rather than being long with very little ame.

A further object is to rovide an inclosing casing for the coil and W 'ch wholly incloses the same, the circuit breaker bei' placed outside of the casing and operated y mag-.- netic action of the coil outside the case eX-. erted through the case upon an armature outside the case and associated with the circuit breaker. f

A further object is-to provide a simple, eflicient, economical and compact construc-' tion of spark coil adapted for general use where s ark coils are required but s eoiall .designe for use in connection with t e igm:

tion devices of ex losive engines;

Other ob'ects oi the invention will appear more fully hereinafter.

.The invention consists substantially in the construction, combination, location and relative arra ement of parts, all as will be more fully hereinafter set forth, as shown in the accompanying drawin s and finally pointed out in the appended c aims.

, Referring to the accompanying drawings and to the various views iind reference signs appearing thereon: Fi re 1 is a view in bottom plan of a s ark coil and its inclosing cas ing and embo ying the principles of my. in-' vention. Fig. 2 is a view in section on the line 2, 2, Fig. 1, looking in the direction of the arrows. F1 .3 is a view in transverse-section on the hue 3, 3, Fig. 2, lookiniin the di-. rection of the arrows. Fig. 4 is a roken detail view in section, showing adjusting means for the platinum screws em loyed in connec' tion with my invention. ig. 5 is a view in end-elevation showing the arrangement of circuit breaker mechanism. Fig. 6 is a broken view in longitudinal section on the line 6, 6, Fig. 5, looking in the direction of the arrows.

The same part is designated by the same reference sign wherhver it occurs throughout the several views.

In the use of spark coils as ordinarily constructed and particularly such coils employed in connection with the ignition devices of explosive engines, the spark pro duced is usually long but has very little tendency to flame. The coil employed for producing the spark commonly has astralght iron wire or other similar core while, usually a comparatively large amount of copper is used in the primary and secondary windings in order to produce the potential required to make the spark. The use of the increased amount of windings of course increases the ohmicresistance of the device and hence also the battery or other source of current consumption, while at the same time, the spark itsel is long and with small power more nearly resembling the spark from a static machine. Moreover, spark coilsemployed in connection with the ignition devices of explosive engines usually require the core to protrude through the casing in order to operate magnetically the circuit breaker, thereby making'it possible for the insulating compound within the casing, when 1i uefied by heat,- to run through, or enabling ust, dirt, air, moisture or other foreign matter to gain access to the interior of the case, thereby corroding the iron or other arts of the coil structure and, hence, rapidly deteriorating the same.

It is among the special purposes of my present inve'ntion'to produce a spark coil device which is very simple and compact 1n construction and arrangement and efiicient in operation, whe rein the magnetic power required in the production of the spark is greatly increased'with a reduced amount of copper in the coil windings, thereby reducing not only the cost of construction but also the amount of current consum tion and of the ohmic resistance, and whic will produce a spark having a tendency to flame and, hence, one that is better suitable for use in insuring gas ignition when used in connection with the ignition devices of explosion engines.

i In carrying out my invention I propose to inclose the coil and its associated magnet core wholly within an inclosing case, and to operate the circuit breaker, by means of the influence of the magnetic field upon an armature placedoutside of the case, the lines of force of the field, generated within the case, operating through the wall of the case, thereenacts by avoiding thenecessity of protruding ,the core through the case.

Referring to the accompanyingdrawings wherein I have shown a construction embodying the principles of'my invention, the

inclosing casing is designated by the reference sign 10. The circuit breaker is designated generally by reference sign 11, and may be of the usual or any well known or convenieht construction, except that it has associated therewith an armature 12, for the oper ation thereof, said armature being 0 erated by the influence of the magnetic fie (1 generated as hereinafter described.

Arranged wholly within the casing 10 are the coils and their associated parts. These, in the particular form illustrated, comprise the primary coil 13, and the secondary coil 14, through which passes the leg 150i the core, the cod crating leg 16 of the core being laced outsi e the coils but having the pole ces 17 of its ends arranged in suitable re-' lation, respectively, with the ends of the leg 15. In practice I prefer to employ a laminated magnet core, both the legs 15 and 16, being com osed of fiat strips or laminations, as clearly s own, and held or bound together in any suitable manner, as, for instance, by-

means of the bindings 18. The pole face of the leg 16 at one end thereof bears against the surface of the core leg 15, while at the other end, namely, the .end where the magnetic field is generated or created for operating the circuit breaker, the pole face of the .one leg is se arated from contact with the other leg su 'ciently far to form an air space 20, therebetween, thereby producing anvinterruption of the magnetic circuit at this point.

In practice I have found that the higher efliciency is attained when the air gap or space 20 is adjusted to the lowest or minimum area which will allow sufficient magnetic leakage to operate the armature 12.

The wiring connections may be and are shown the same, as those ordinarily employed in connection with devices of this nature.

I have found that an induction coil having primary and secondary windings and a laminated magnetic circuit, nearly closed, or having an air space or gap, as above described, is well adapted for my purpose, and that when the air space or gap is of sufficient extent to give the requisite magnetic leakage through the wall of the inclosing case to move an armature to operate the circuit breaker,less copper is required. in the windings of the primary and secondary, more energy 18 developed in, the magnetic field the ohmic resistance losses are less, and a spark of more suitable character for efficient service in connecting igniting devices for explosive eni'nes is reduced, than with spark coils as eretoore commonly constructed and now in use.

crate through the casing, which may be of wood, fiber, or any non-magnetic metal, and in practice, where a metal casing is employed, I prefer to make that portion of the same lying between the circuit breaker armature and the coil Within the casing of nonmagnetic material having a high electrical resistance, such, for instance, as brass, otherwise the action of the armature is impeded or made more sluggish by induced currents generated in that part of the case.

The e'flect of the metal case on the magnetic field, that is the sluggishness reduced by such case on that portion oft e magnetic field which passes through the case, does not in any way impede the velocity of the magnetic lines which lie entirely within the casing, nor does the metal case appear to impede the speed of that portion of the magnetic lines which lie within the case but which also ass through the case to the armature. Hibwever, such magnetic lines,

' when the primary circuit is open, will rapidly close that portion of the path of such lines which lies inside the case, and then disappear as a current eddy near the armature, and if the secondary is closed the spark produced by these magnetic lines will dissipate a large portion of their energy on the secondary circuit. That the velocity of the magnetic lines, generated by the apparatus as above described, is very great in closing on the secondary when the primary circuit is open can be understood from the fact that a core of one centimeter cross sectional area and magnetization of ten thousand maximills can produce a secondary otential oi five volts per turn of winding which is equal to a velocity of more than ten thousand meters per second. The feature of inclosing the coil wholly within the case I regard as a very important feature of my invention for the reason that thereby protection is afforded against danipness, moisture, dust and the like while at the same time variations of temperature do not afiect the a paratus or its operation. These are particuihriy useful and valuable charac teristics where the device is employed in connection with sparking devices oi explosion engines used on automobiles. Iii-such held of. use the casings containing the coils may be readily and easily mounted in any convenient and accessible place and which may be readily detached while. presenting a neat and finished appearance. I

In Fig. 4, I have shown a specialform of adjustment which may be employed for the platinum screws used in connection with the apparatus. The adjustment of these screws is the only adjustment necessaryabout the apparatus. In the ordinary formof. adjustment either a lock nut is employed for locking the screw in its adjusted position or else a ratchet adjustment is employed. The former method of adjustment is objectionable for the reason that the operation of turning up the lock nut tight disarranges the adjustment of the screw. The ratchet form ofadjus'tment is objectionable for the reason that adjustments are thereby effected in steps .and cannot be made very close. To -overcome these objections I employ a specially formed bushing 25, into which the platinum screw 26 extends, the end of such screw being received in a separate locking screw 27,. mounted in the bushing 25, but insulated therefrom. By this construction the'platinum screw is locked without in any way changing its adjustment.

It is to be understood that many variations and changes in the details of construc tion and arran ement might readily occur to ersons skilIed in the art and still fall wit in the spirit and scope of my invention. I do not desire, therefore, to be limited or restricted to the exact details of construction and arrangement shown and described. But having now set forth the object and nature of my invention, and a construction embodying the principles thereof, and having-described such construction, its purpose, function and mode of operation,

What I claim as new and useful and of my own invention and desire to secure by Letters Patent is:

1. A high potential spark coil having an air gap formed transversel through the magnetic circuit thereof,-an inclosing casing for said coil, and an armature arranged outside the casing and adapted to be 0 erated by the magnetic field generated wit in the casing. 4

2. In a high potential spark coil an inclosing casing, means arranged within the casing for generating a magnetic field, and a movable armature arranged outside the case. and ada ted to be 0 erated by the influence of sai magnetic fie d.

3. A high otential spark coil having an air gap forme transversely through the magnetlc circuit thereof, an inclosing casing for the coil and a movable armature arranged outside the casing and adjacent the air gap.

'4. A high potential spark coil having a primary and a secondary winding, a core therefor, said core having an air gap'ln the magnetic 'mary and a secondary winding and a core therefor, said core having an air ap in its magnetic circuit, a casing for who 1y inclosing said windings and core, and a movable armature arranged outside the casing and at a point adjacent said air ga 6. A high potential spar coil having a laminated core, said core having arr air ga formed throu h the magnetic circuit thereo and a movabe'arm'ature arranged opposite the air gap to be operated by the magnetic field at th s point.

7. A high potential spark coil having 'a laminated core, said core having an air gap through themagnetic circuit thereof, an inclosingcasing for said coil and core, and a movable armature arranged outside the casing, opposite the air ap in the core.

8. A high potentiafi spark coil including a primary and a secondary winding and a laminatedcore, said core having an air gap tnansversely throu h the magnetic field thereof, and a movab e armature arranged opposite said air ga 9. A high potential s ark coil including a rimary and a secon ary winding and. a aminated-core, said core having an air gap transversely through the magnetic field thereof, an inclosing casing for said coil, and a movable armature arranged outside the casing andat a point 0 posite the air gap.

10. A high potentia spark coil including a core having an air gap formed transversely throu h the magnetic circuit thereof a non magn tic metal case inclosing said coil and core, and a movable armature arranged outside the case and at a point opposite the air a 3 I1. A high potential spark coil including a core having an air ga transversely through the magnetic circuittiiereof, a metallic case wholly inclosing said coil and core and having a non-magnetic wall opposite said air gap, and a movable armature arranged outside the casing and opposite said non-magnetic wall.

12. A high potential s ark 001l having a core, said core provide with an air gap through the magnetic circuit thereof, inr eom- CHESTER H. THORDARSON.

Witnesses:

WALTER QUITMAN, SYLVANUS E. LAMBERT.

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